Drill supports or drill stands of this type are well known and consist of a support which is secured to the workpiece so that the drill can be secured and positioned on the stand to effect accurate drilling or machining of the workpiece.
Hitherto drill supports of this type comprised an electromagnet which was used to secure the support to the workpiece. Such electromagnets rely on an electric current which is turned on to secure the support in position and off to enable movement of the support to the correct position. The electric current has to be maintained to secure the support to the workpiece. If the electric current is interrupted either by accident or by a power failure the support will be no longer secured to the workpiece. This can be very dangerous when it occurs during machining of the workpiece. Current interruption is especially dangerous when the workpiece is vertical or must be machined from below. In such cases chains are sometimes provided to prevent the drill from falling in the event of a power failure. However sometimes the chains are not attached due to forgetfulness or inconvenience and the consequences in the event of power failure are very dangerous particularly if the workpiece is located high above the ground as would be the case during construction of a tall building.
The drill support of the present invention avoids all these safety problems of existing drill supports by using a permanent electro magnet instead of conventional electromagnets. Such permanent-electro magnets do not require a continuous electric current to secure the support to the workpiece because the holding power is provided by the permanent magnets. An electrical power failure will not result in any loss of magnetic holding power. The permanent-electro magnet uses an electrical current merely to switch the magnet on and off.